The rongeur is a medical instrument used for a variety of purposes. It is particularly useful for removing small amounts of bone, cartilage or other body material from inside small spaces of the knee or between vertebrae of the back. A rongeur usually includes a long fixed shank with an anvil or footplate at its distal end and a handle at its proximal end. A reciprocating shaft or crossbar moves axially with respect to the fixed shank, either inside a hollow fixed shank or along the outside surface of a rigid fixed shank. A cutter on the distal end of the reciprocating crossbar abuts the footplate to cut tissue captured between the cutter and the footplate. The proximal end of the crossbar is attached to some sort of trigger mechanism for reciprocating the crossbar and moving the cutter against the footplate.
Very large forces are experienced at the footplate of the rongeur when the surgeon is cutting hard material like bone or cartilage. Conventional rongeur designs have always had to compromise between the size and strength. It is desirable to have the footplate and the whole distal end of the rongeur as small as possible so that it can fit into the confined spaces where it is usually used. However, if one makes the footplate too small one begins to become concerned about whether the tip is strong enough withstand the forces applied to it during cutting. It would be desirable to have a rongeur with a very thin footplate portion so that it could fit into the small spaces one finds particularly in surgery of the back and still provide adequate strength for the mechanical parts of the rongeur.